The cGMP-dependent protein kinase pathway in platelets

血小板中 cGMP 依赖性蛋白激酶途径

• 批准号: 7819163
• 负责人: Xiaoping Du
• 金额: $ 1.95万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7819163
• 关键词: Adhesions; Agonist; Alpha Granule; Atherosclerosis; Blood Platelets; Blood Vessels; Chronic; Cyclic AMP; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Cytoplasmic Granules; Data; Development; Disease; Figs - dietary; Funding; Human; Injury; MAPK14 gene; Mediating; Mitogen-Activated Protein Kinases; Myocardial Infarction; Nitric Oxide; Nitric Oxide Donors; Nitric Oxide Synthase; Pathway interactions; Phosphatidylinositols; Phosphotransferases; Platelet Activation; Platelet aggregation; Play; Production; Protein Isoforms; Regulation; Research Personnel; Role; Signal Pathway; Signal Transduction; Site; Soluble Guanylate Cyclase; Stroke; Testing; Thrombosis; human NOS2A protein; human NOS3 protein; novel; programs

Platelet activation play critical roles in the development of thrombotic diseases such as heart attack and stroke. The roles of platelets in thrombosis involves two major aspects: Firstly, platelet adhesion, aggregation and secretion of granule contents are important in the development of atherosclerosis, which causes chronic vascular injury. Secondly, platelet activation at the site of vascular injury is critical in initiating arterial thrombosis. An intracellular secondary messenger molecule, cGMP, is synthesized during platelet activation. The role of cGMP in platelet activation has been controversial since the discovery of cGMP. It has been a prevailing concept in the past 30 years that cGMP, by activating the cGMP-dependent protein kinase (PKG), inhibits platelet activation. This concept, however, has been challenged by our recent finding that cGMPand PKG play a biphasic role in platelet activation, We show that cGMP plays a stimulatory role when low concentrations of cGMP is produced upon platelet agonist stimulation, but becomes inhibitory at high cGMP concentrations. During the last funding period, we have made significant progress in understanding the mechanisms of the biphasic roles of the cGMP pathway in platelet activation. We have found that the cGMP-PKG pathway plays a general role in stimulating platelet secretion and secretion-dependent platelet aggregation induced by most platelet agonists. We have obtained evidence supporting a new upstream signaling pathway of cGMP during platelet activation involving phosphoinositide 3-kinase, various forms of Akt and nitric oxide (NO) synthase. We have also obtained evidence supporting a novel downstreamsignaling mechanism of cGMP involving various isoforms of PKG and PKG-dependent sequentially activation of p38 and ERK mitogen-activated protein kinase pathways. These discoveries allow us to hypothesize a novel signaling pathwaythat stimulates platelet secretion. In this pathway, platelet agonists, by activating different isoforms of PI3K, Akt, NOS3,soluble guanylyl cyclase, and PKG, and via the p38 and ERK pathways, induce platelet secretion, which amplifies and stabilizes platelet aggregation. To test this hypothesis, we propose following specific aims: 1.To investigate the role of different Akt isoforms as upstream activators of the cGMP pathway during platelet activation. 2. To determine mechanisms of agonist-induced platelet NO production, its regulation, and its role in platelet secretion and aggregation. 3.To characterize the roles and the signaling mechanisms of different isoforms of PKGin platelet secretion and aggregation.

血小板活化在血栓性疾病如心脏病发作和中风的发展中起关键作用。的 血小板在血栓形成中的作用涉及两个主要方面：一是血小板粘附、聚集和分泌 颗粒内容物在动脉粥样硬化的发展中是重要的，动脉粥样硬化导致慢性血管损伤。第二、 血管损伤部位的血小板活化在引发动脉血栓形成中是关键的。一种细胞内次级 信使分子cGMP在血小板活化过程中合成。cGMP在血小板活化中的作用已被证实。 自cGMP被发现以来就一直备受争议。在过去的30年里，cGMP一直是一个流行的概念， 激活cGMP依赖性蛋白激酶（PKG），抑制血小板活化。然而，这一概念一直 受到我们最近发现cGMP和PKG在血小板活化中起双向作用的挑战，我们发现cGMP 当血小板激动剂刺激后产生低浓度cGMP时， 在高cGMP浓度下抑制。在上一个资助期内，我们在以下方面取得了重大进展 了解cGMP途径在血小板活化中的双相作用机制。我们发现 cGMP-PKG通路在刺激血小板分泌和分泌依赖性血小板聚集中发挥普遍作用 由大多数血小板激动剂引起。我们已经获得证据支持一个新的上游信号通路的cGMP 在血小板活化过程中涉及磷酸肌醇3-激酶、各种形式的Akt和一氧化氮（NO）合酶。我们 我也获得了证据支持一种新的下游cGMP信号机制，涉及各种异构体 PKG和PKG依赖的p38和ERK丝裂原活化蛋白激酶途径的顺序激活。这些 这些发现使我们能够假设一种新的刺激血小板分泌的信号通路。在这条通路中，血小板 激动剂，通过激活PI 3 K、Akt、NOS 3、可溶性鸟苷酸环化酶和PKG的不同亚型，并通过p38和 ERK途径诱导血小板分泌，其放大并稳定血小板聚集。为了验证这个假设，我们 本研究的主要目的如下：1.研究不同Akt亚型作为cGMP上游激活因子的作用 血小板活化的途径。2.为了确定激动剂诱导血小板NO产生的机制， 调节，以及其在血小板分泌和聚集中的作用。3.描述角色和信号机制 不同亚型的PKG在血小板分泌和聚集中的作用。